Field of the Invention
The invention relates to a detonator device having a detonator circuit for tripping a passenger restraint device in a motor vehicle.
One system for tripping a passenger restraint device in a motor vehicle is known from European Patent Application EP 0 471 871 A1. The system has an evaluation unit, disposed centrally in the vehicle, for evaluating acceleration and crash signals that are furnished by a sensor device. Detonator devices that include detonator circuits are disposed near the associated passenger restraint devices, such as an air bag, belt tensioner, and so forth, are connected to the evaluation unit via a line/bus. If the evaluation unit detects an accident in which at least one of the passenger restraint devices should be tripped, then an encoded trip command is sent from the evaluation unit to the corresponding detonator device. In the detonator circuit of the detonator device, the trip command is decoded and converted into control commands, by which the energy, stored in an energy-storing capacitor of the detonator device, is transmitted to a passenger restraint device detonator element/primer capsule that is electrically connected to the detonator device.
A conventional detonator element in the form of a primer capsule has two firing pins that are connected via a detonator wire. The detonator wire is disposed in a firing chamber, which is formed by both a holder of the primer capsule and a plastic cap. The firing chamber is filled with a detonating powder, which when the detonator wire heats up sufficiently explodes and blows off the lid of the plastic cap. The sheath of the plastic cap is surrounded by a metal cap that is intended to prevent electromagnetic radiation into the firing pins and detonator wire. A lower part of a gas generator sheath surrounds the primer capsule and at the same time forms a plug body for the firing pins. The gas generator sheath surrounds a generator chamber, in which capsules are disposed that are supplied with energy by the explosion of the detonating powder and thereupon release gases which fill an air bag connected to the gas generator. via the plug connection, the primer capsule is electrically conductively connected to an evaluation unit disposed centrally in the vehicle, and for tripping the associated passenger restraint device, a firing pulse that carries sufficient energy is transmitted via a line between the evaluation unit and the primer capsule.
The known primer capsule typically has a short-circuit bridge disposed between the firing pins. Such a short-circuit bridge prevents unintended detonation of the detonating powder, by unintentional application of a direct voltage to the firing pins protruding from the plug body, before a mating plug is plugged into the primer capsule.